Artificial hand and means for actuating the same



ARTIFICIAL HAND AND MEANS FOR ACTUATING THE SAME Filed Dec. 14, 1942 3Sheets-Sheet l IINVENTOR. FRANK 1 EBA-R45 Aug. 14*, LE ARTIFICIAL HANDAND MEANS FOR ACTUATING THE SAME 3 Sheets-Sheet 2 Filed Dec. 14, 1942 if58 65a 1 65 56 I 6/ i G 4 o I I [3 625 l 24/ 4T TOE/VEV g 1945' F. v.EBERLE ARTIFICIAL HAND AND MEANS FOR AGTUA-TING THE SAME Filed Dec. 14,1942 3 Sheets-Sheet 5 INVENTOR. FRANK 1 EBEELE BY Mia 27% Patented Aug.14, 1945 OFFICE ARTIFICIAL HAND AND MEANS FOR ACTUATING THE SAME FrankV. Eberle, Newark, N. J.

Application December 14, 1942, Serial No. 468,950

6 Claims.

This invention relates to artificial limbs and more particularly to animproved artificial hand and means for actuating the same. Thisapplication is a continuation-in-part of my co-pendlng patentapplication, Serial No. 443,889, filed May Another object is to providea novel and i proved means controlled by the movement of the remaininglimb stump for actuating the artificial hand.

Other objects and advantages inherent in the invention will becomeapparent from the following specification taken in conjunction with theaccompanying drawings which disclose by way of example an embodiment ofthe invention together with possible modifications.

Artificial appliances have heretofore been used to replace the missingmember. However, because of the unsatisfactory experiences with theordinary mechanical limb, attention has been directed toward thedevelopment of a substitute limb in which the control can be achieved bythe movements of the remaining limb stump. In order to accomplish theintended purpose, it is imperative that the artificial limb be highlysensitive and immediately responsive to even minor impulses produced bythe limb stump.

It is,. therefore, the particular purpose of the present invention toprovide an artificial limb in which prosthesis can be activated byimpulses provided by the limb stump.

In the drawings:

Figure 1 is a cross-sectional view of an artificial hand according tothe invention with the adjacent portions of the wrist and the actuatinglever mechanism;

, Figure 2 is a top plan view with the top plate removed:

Figure 3 is a detailed view of the locking mechanism;

Figure 4 is a plan view of the mechanism transmitting impulses of thearm stum to the lever mechanism of the artificial hand;

Figure 5 is a side view of Fig. 4 with a portion broken away;

Figure 6 is a side view of a modification together with a portion of thestump in which the prosthesis is activated by the mechanical movement ofthe stump;

Figure 7 is a side view of another modification together with a portionof the stump for mechanical activation of the prosthesis;

Referring in detailto the drawings, a frame or casing Ill represents thepalm and the back of the hand. The front portion of casing I0 isprovided with an opening I I in which the knuckle portions of fingers l2are pivoted on a shaft l3.

The thumb I4 is similarly pivoted to a shaft l8 and extending through anopening l5 of casing l0.

An arched actuating lever ll extends from the knuckle portion of thefingers l2 into the casing I ii. A corresponding arched lever l8 extendsfrom the thumb M in opposite relationship to a lever l1. Levers IT andI8 are so disposed that their ends move in substantially parallel planestoward and away from one another.

A crank I9 is keyed to the shaft 20 which is rotatably mounted in a boss2|, which latter is preferably cast integrally with casing Ill.

An arched link 22 connects lever l1 to the crank 19. A second straightlink 23 connects the lever I8 to crank l9. The pivot point of the link23 is spaced from the pivot point of link 22 on crank it for the purposeof providing the relative movement between fingers I2 and thumb I t.

Crank I9 is actuated by a linear movement of a rod 2 lwhich is pivotedto a pin which, in turn, is anchored to crank i9.

To shaft 20 is also keyed a toothed segment 28 so as to move jointlywith crank it. A pawl 21 cooperates with toothed segment 28 and ispivoted at 28 to a lever 29 which, in turn, is journaled at 20 to boss 2l.'

Lever 29 has an arm 3|, the end of which is connected to the inside ofthe casing ill by means of a heavy spring 32. A light spring 88 connectspawl 21 with a second arm 34 of lever 29. By virtue of thisconstruction, the pawl will become disengaged from the toothed segment26 immediately upon release of the'locking mechanism,

which will be hereinafter described, and jump back to its normalposition. The arm it limits the return movement of the lever 29 bystriking the underlying surface of the casing Hi; this position is shownin Figure 3.

The locking mechanism comprises a plate 35 which is pivoted at 36 to aboss 37. The plate is rotatedby a lever 38 which projects into the palmthrough the opening 39 in casing Ill. A link an is pivoted at one end toplate 35 and at the other end to pawl 21 eccentrically of pivot point 28of pawl 21.

When lever 38 is pushed forward in the direction of the arrow in Figure3, it first brings the pawl into engagement with the toothed segment 28against the strength of spring 38 and without rotation of segment 28.Further movement of the lever 38 will rotate the segment 28 togetherwith the crank l8 and thus bring the fingers i2 and the thumb i4 tighttogether. The various levers and pivot points are arranged so thatspring 82 will lock lever 88 in its forward looking position. By reasonof this construction the force of the grip can be increased once contacthas been made between the object and the fingers and the thumb and atight grip of small objects is secured. It will also be understood thatthe fingers and thumb can be locked in any position intermediate thefully opened and fully closed position.

The casing i8 is providedwith a wrist collar 4| which may be rotatablewith respect to the casing so as to provide pronation and supination ofthe hand. To the wrist collar 4! is attached a cuflf 88 by any suitablemeans.

As shown in Figures 4 and 5, the prosthesis is activated by the movementof the limb stump. The limb stump is supported in a cup 58 which ispivoted at 88 to braces 81 fastened to a support 88. This support issecured to the limb stump by any suitable means. Braces 81 are pivotedto brace 88 at 8i to form an elbow joint. Braces 88, in turn, arefastened to the cuif 88. The casing I8 is rotatably mounted in the cuff88, as illustrated in Figure 1. Rod 24 is connected to one arm of alever 82 by means of a link 83, but is rotatable in relation to saidlink. This is attained by providing the end of rod 24 with a flangewhich is rotatable in a suitable recess provided in the member 88. Theother arm of lever 82 is pivoted to a shackle 84 which at the other endis connected to braces 81 by a pivot 88a. Shackle 84 is bent at 88 so asto cause longitudinal movement of the shackle 84 and a pivotal movementof lever 82 when the stump and the cup 88 are moved. The lever 82 ispivotally supported at 82a upon a support 82b connected to the cuif 88.

An artificial limb according to my invention is operated as follows:

If the artificial hand is to be opened or closed, the person using thehand moves cup 88, for example, by bending his limb stump. Any movementoi cup 88 causes an upward or downward movement of shackle 84 which, inturn, will rock lever 82. Assuming that the right arm of lever 82 ismoved downward, rod 24 will be pushed into the hand. This movement ofrod 24 will cause crank l8 to pivot about its axle 28. The pivotalmovement of crank i9 is transferred to fingers l2 b links 22 and I 1 andto thumb it by links 23 and Hi. It is obvious from Figs. 4 and theoriginal movements of cup 88 will be transmitted to the artificial handat an increased ratio so that even slight movements of the limb stumpwill be sufiicient to actuate the hand.

As previously explained, a movement of rod 24 into the hand will resultin an opening of the hand. Conversely a retraction of the rod 24 fromthe hand by an opposite movement of cup 88 will cause a closing of thehand. The locking device permits a locking of the fingers and the thumbin any desired intermediate position. It also secures a tight grip onany small object. If a hard object is-to be gripped between the fingersthe user of the hand first closes his fingers as tight as he is able todo by a movement of the limb stump or with his good hand. Then lever 88of the locking device, located in the palm of the hand, is slowly pushedupwards. Light spring 38 will close the fingers partly but not tootight.

The final tightening is made by heavy spring 82. In other words, if ahard object is to be gripped, the light spring will yield to a certainextent and permit a closure of the above-described locking devicewithout any strain on any part of the lock, yet the hard object will besecurely gripped betweenthe fingers.

In the modification shown in Figure 8, the prosthesis is activated bymovement of the stump supported in a cup 88. A two-arm lever 81 which ispivoted to a brace 88 is rocked by the movement of cup 88 by means of aleverage mechanism including links 88 and 18 which are pivoted to across-bar II. The brace 88 is connected at 88a to the cup 88. One end ofcross-bar H is connected to one arm of lever 81 by means of a link T2.The other end of cross-bar H is pivoted to a bell crank 13 which, inturn, is pivoted to the other arm of lever 81. A second leveragemechanism includes the following parts. Bell crank I8 is connected bymeans of a link 16 to one arm of another bell crank 15 which is pivotedat 18 to a brace 11. The other-arm of bell crank 18 is pivoted to rod24. The joint between braces 88 and 11 corresponds to the elbow joint inthe arm which is activated by separate means not forming part of theinstant invention.

As it is apparent from Fig. 6, movements of cup 88 will result in arocking of lever 81. The rocking motion of lever 81 is transmitted bybellcrank 13, link I4 and bell-crank '|8 to rod 24. Due to thearrangement of the various links and bell-cranks, the original impulseproduced by a movement of cup 88 will be conveyed to the hand at anincreased ratio.

A movement of cup 88 in one direction will causea movement of rod 24resulting in an opening of the hand as previously explained, and amovement of cup 88 in the opposite direction will result in a retractionof rod 24 from the handle and hence in a closing of the hand.

Figure 7 shows another modification wherein the prosthesis is activatedby the mechanical movement of the stump. A lever 18 is pivoted to abrace 18. One arm of lever 18 is connected through a link 88 to abracket 8| which is fixed to a cup 82. The other arm of lever 18 isconnected through a link 83 to a bell crank 84. Bell crank 84 is. inturn, pivoted to a bracket 88 which is anchored to brace 19. The otherarm of bell crank 84 is connected to actuating rod 25.

A movement of cup 82 will be transmitted, by link 88 to lever 18 andcause a rocking movement of this lever. The movements of lever 18 willbe conveyed by link 83 to the rod 24 and cause an opening or closing oithe hand as previously explained. It will be noted that the arrangementof the various levers and links results in a transmission of the cupmovements at an increased ratio. The wrist collar 4| shown in Figure 1may be conveniently employed in connection with the devices shown inFigures 6 and '7.

It will be understood that the invention has been described by way ofexample and not by way of limitation. The invention lends itself to avariety of expressions within the scope of the appended claims.

What is claimed is 1. An artificial limb comprising an artificial handincluding a frame, a series of fingers and a thumb pivoted to saidframe, a pair of arcuate levers connected to said fingers and thumb toopen and close the hand, said levers being disposed in opposingrelationship with their free ends movable in substantially parallelarcs, a

crank, a longitudinally movable rod for actuating said crank, a linkconnecting each of said levers with said crank, said links being sodisposed as to transform the linear movement of said rod into' thepivotal movement or said fingers and thumb, a toothed rackmovable withsaid rod and connected to said crank, a pawl for engaging said rack, aleverage'mechanism connected to said pawl for moving said rack apredetermined distance, a two-armed lever pivoted to said pawl, a lightspring between one arm of said lever and said pawl whereby said pawlwill be disengaged from said rack immediately upon release oi saidleverage mechanism, a second heavier spring between said lever and saidframe for locking said pawl in a predetermined position oi said leveragemechanism and means controlled by the remaining stump for moving saidrod.

2. An artificial limb comprising an artificial hand including a frame, aseries of fingers and a thumb pivoted to said frame, a pair of arcuate'levers connected to said fingers and thumb to open and close the hand,said levers being disposed in opposing relationship with their free endsmovable in substantially parallel arcs, a crank, a longitudinallymovable rod for actuating said crank, a link connecting each of saidlevers with said crank, said links being so disposed as to transform thelinear movement of said rod into the pivotal movement of said fingersand said thumb, a toothed rack movable with said rod and connected tosaid crank, a pawl for engaging said rack, a leverage mechanismconnected to said pawl for moving said rack a predetermined distance, atwo-armed lever pivoted to said pawl, a light spring between said leverand said pawl whereby said pawl will be disengaged from said rackimmediately upon release of said leverage mechanism, a second heavierspring between said lever and said frame for locking said pawl in apredetermined position of said leverage mechanism, and means controlledby the remaining stump for moving said rod, said means including aleverage mechanism for actuation by said limb stump and a link mechanismfor transmitting the movement of said latter leverage mechanism to saidrod.

3. An artificial limb comprising an artificial hand including a frame, aseries of fingers and a thumbpivoted to said frame, a pair of arcuatelevers connected to said fingers and thumb to open and close the hand,said levers being disposed in opposing relationship with their free endsmovable in'substantially parallel arcs, a crank, a longitudinallymovable rod for actuating said crank, a link connecting each of saidlevers with said crank, said links being so disposed as to transformthelinear movement of said rod into the pivotal movement of said fingersand said thumb, a toothed rack movable with said rod and connected tosaid crank, a pawl rod, said means including a leverage mechanism foractuation by said limb stump and a link mechanism for transmitting themovement of said latter leverage mechanism to said rod at an increasedratio.

4. An artificial limb comprising an artificial hand including a frame, aseries of fingers and a thumb pivoted to said frame, a pair of arcuatelevers connected to said fingers and thumb to open and close the hand,said levers being disposed in opposing relationship with their free endsmovable in substantially parallel arcs, a crank, a longitudinallymovable rod for actuating said crank, a link connecting each of saidlevers with said crank, said links being so disposed as to transform thelinear movement of said rod into the pivotal movement of said fingersand thumb and means controlled by the movements of remaining stump ofthe natural limb for moving said rod, said means including a cup securedto said limb stump, a leverage mechanism for actuation by movements ofsaid sturnma two-arm lever actuated by said leverage mechanism, a secondleverage mechanism actuated by said two-arm for engaging said rack, aleverage mechanism connected to said pawl for moving said rack apredetermined distance, a two-armed lever pivoted to said pawl, a lightspring between said lever and said pawl whereby said pawl will bedisengaged from said rack immediately upon release of said leveragemechanism, a second heavier spring between said lever and said frame forlocking said pawl in a predetermined position of said leveragemechanism, and means controlled by the remaining stump for moving saidlever for transmitting the movement of said twoarm lever to'said rod.

5. An artificial limb comprising an artificial hand including a frame, aseries of fingers and a thumb pivoted to said frame, a pair of arcuatelevers connected to said fingers and thumb to open and close the hand,said levers being disposed in opposing relationship with their free endsmovable in substantially parallel arcs, a crank, a longitudinallymovable rod for actuating said crank, a link connecting each of saidlevers with said crank, said links being so disposed as to transform thelinear movement of said rod into the pivotal movement of said fingersand thumb and means controlled by the movements of the remaining stumpof the natural limb'for moving said rod, said means including a cupsecured to said limb stump, a pivotally supported two-arm lever, aleverage mechanism connectin said cup to one arm of said two-arm leverfor transmitting movements of said cup to said arm and a second leveragemechanism connecting said rod to the second arm of said two-arm leverfor transmitting movements of said two-arm lever to said rod.

6. An artificial limb comprising an artificial hand including a frame, aseries of fingers and a thumb pivoted to said frame, a pair of arcuatelevers connected to said fingers and thumb to open and close the hand,said levers being disposed in opposing relationship with their iree endsmovable in substantially parallel arcs, a crank, a longitudinallymovable rod for actuating said crank, a link connecting each of saidlevers with said crank, said links being so disposed as to transform thelinear movement of 'said rod with the pivotal movement of said fingersand thumb and means controlled by the movements of the remaining stumpof the natural limb for movin said rod, said means including a cupsecured to said limo stump, a pivotaily supported two-arm lever, abell-crank pivotaliy connected to one arm of said two-arm lever, aleverage mechanism connecting said cup with one arm of said bell-crank,a second pivotally supported bell-crank, a link connecting one arm ofsaid first bell-crank to one arm of said second bell-crank and a pivotalconnection between the other arm of said second bell-crank and. saidrod.

FRANK V. EBERLE.

